Is there another way besides particles to make fire in the game engine?
You can add a transparent animated plane.
First off, you must change the Shading from Multitexture to GSL.

it must be tiled and evenly spaced like the image below


Because there are four tiles you would check the animated button, and choose one tile along the Y and 4 along the X



you also need to input a frames per second, and how many frames the animation should run for.



Blend file with working animated transparent plane